CardioNerds (Amit Goyal & Daniel Ambinder) join Dr. Rayan Jo Rachwan, Dr. Anupama Joseph, and Dr. Mohammed Merchant from the University of Wisconsin-Madison for a classic Madison dinner cruise! They discuss the following case: Mixed shock secondary to severe right ventricular outflow tract obstruction with Gemella Haemolysans prosthetic pulmonary valve endocarditis in a young patient with Shone Complex (syndrome). Dr. Ford Ballantyne III provides the E-CPR segment for this episode. Special introductory music composed by Dr. Rayan Jo Rachwan. We are excited to welcome University of Wisconsin- Madison to the CardioNerds Healy Honor Roll and Dr. Rayan Jo Rachwan as the CardioNerds Ambassador.
A 26-year-old male with history of bicuspid aortic valve and Shone Complex (syndrome)—status post coarctation repair, subaortic resection and Ross-Konno operation—presenting with 3 months of constitutional and respiratory symptoms. Initial evaluation demonstrated that patient was in a state of mixed shock due to a large pulmonary Melody valve thrombus with superimposed Gemella Haemolysans prosthetic valve endocarditis. He required treatment with inotropes, pressors, followed by intubation and extracorporeal membrane oxygenation (ECMO). Patient was treated initially via right heart catheterization with balloon dilation and stent placement to his right ventricle-to-pulmonary artery conduit, which lead to significant improvement in his hemodynamics. Patient was then decannulated from ECMO, extubated, weaned off pressor support and later underwent a successful surgical resection of the infected pulmonary homograft and Melody valve/stents and replacement with pulmonary-valved conduit. He was also discharged on a prolonged course of antibiotics.
Case Media – Shone Complex
A. CXR, B. ECG, C. TV Doppler, D. PV Doppler
•Melody pulmonic valve repair with large thrombus arising from the mid-distal valve extending into the main pulmonary artery and proximal left pulmonary artery. Evaluation for distal subsegmental pulmonary emboli is limited. •Tiny focus of air in the thrombus may be related to contrast injection. Infection is less likely. •Enlarged right heart chambers, may be in part chronic right heart enlargement and/or new right heart strain. No pulmonary infarct.
CT chest abdomen and pelvis with contrast
•Findings suggestive of acute hepatitis and acute pancreatitis. No pancreatic hypoenhancement or peripancreatic fluid collection. •No abscess within the abdomen or pelvis. •Small caliber of the infrarenal abdominal aorta and bilateral iliac arteries, probably congenital.
Episode Teaching – Shone Complex
1. Patients with congenital heart disease are more predisposed to infective endocarditis (IE). Therefore, there should be a low-threshold for infectious workup in the case of unexplained fever or malaise without associated symptoms for >72 hours. Every routine visit should screen for symptoms and signs of IE.
2. Treatment of right ventricular (RV) outflow tract obstruction with balloon dilation +/- stenting can be considered as a bridge to valve replacement in the case of severe hemodynamic compromise; thus, restoring RV and pulmonary artery coupling. As with many complex decisions this should be made in consultation with an experience heart team and shared decision making with the patient or proxy.
3. Patients with RV volume and/or pressure overload from right-sided valve etiology should be assessed serially (i.e., yearly) with transthoracic echocardiography.
4. When precise quantitative data about the RV is required to make important clinical decisions (e.g., when to recommend pulmonary valve replacement), cardiac magnetic resonance imaging (CMR) remains the diagnostic modality of choice.
5. Repairing or replacing the pulmonary valve should be considered when RV end-diastolic volume >160 mL/m2 and/or RV end-systolic volume >80 mL/m2 on CMR.
- What is Shone syndrome?
- Shone syndrome (a.k.a. Shone anomaly, Shone complex) is a rare congenital abnormality that accounts for 0.6% of all congenital abnormalities.
- It is characterized by a series of left-sided obstructive lesions. The diagnosis is made with the presence of at least 3 of 8 described lesions.
- The 8 described lesions are:
- Cor Triatriatum
- Supramitral ring
- Parachute mitral valve
- Subaortic stenosis
- Bicuspid aortic valve and small aortic valve annulus
- Coarctation of the aorta
- Hypoplastic (stiff) left ventricle.
- Small aortic arch
- Supravalvular mitral ring, parachute mitral valve, subaortic stenosis, and coarctation of the aorta were the first four described lesions and constitute the classic constellation of Shone complex.
- Incomplete forms involve an LV inflow lesion plus at least one LV outflow lesion.
- Frequently, coarctation of the aorta is recognized before the other defects are detected. The coarctation may mask the effects of the other lesions and some patients with Shone syndrome are only diagnosed when symptoms persist after coarctation repair.
- How does Shone syndrome manifest?
- The symptoms associated with Shone syndrome are mostly symptoms of congestive heart failure (which can occur in the first week of life), potentially presenting in early childhood as fatigue, rapid breathing and wheezing, faster than normal heart rate, poor oral intake, poor weight gain, fluid retention (edema) in the legs, pallor (anemia), and frequent pneumonias.
- In a series of 28 adult patients with Shone syndrome followed for a median of 8 years (Aslam et al., CJC 2016), nearly half had cardiovascular hospitalizations during adulthood, mostly for arrhythmias or heart failure.
- The severity and prognosis depend on the individual lesions involved and the degree of obstruction to flow they cause.
- How is Shone syndrome diagnosed?
- Diagnosis involved multimodality imaging predominantly with TTE, as well as TEE, CMR, and/or cardiac CTA as useful adjuncts depending on the lesions and patient age.
- Invasive hemodynamics and angiography are important adjuncts, particularly while planning repair.
- How is Shone syndrome treated?
- It is treated by addressing each of the constituent defects. For example:
- Coarctation of the aorta:
Treated surgically with excision with end-to-end anastomosis or subclavian flap angioplasty. Alternatively, it can be treated with transcatheter balloon angioplasty, particularly in the case of re-coarctation after surgical repair.
- Subaortic stenosis:
Treated surgically by excising the excess tissue below the aortic valve. If other forms of aortic stenosis are present, surgical repair may involve the replacement of the aortic valve.
- Mitral stenosis (caused by “parachute” mitral valve and by supravalvular mitral membrane):
Treated by surgery (valve replacement vs. valve repair).
- Coarctation of the aorta:
- What is the prognosis of patients with Shone syndrome?
- The long-term prognosis for patients with Shone syndrome is difficult to predict and is extremely variable depending on the lesions involved and degree of obstruction.
- It depends on the extent of mitral valve disease, the degree to which the left ventricle is hypoplastic, and the cumulative effects of surgical treatments.
- Moreover, patients who develop pulmonary arterial hypertension (PAH) have a poorer prognosis. Early surgical intervention is important to prevent the adverse consequences of long-standing obstruction and ensuing PAH.
- How are patients with Shone syndrome followed-up?
- With regard to right ventricular (RV) assessment, echocardiography (more widely available) provides useful diagnostic information in many clinical circumstances that affect the right heart.
- However, when precise quantitative data is required to make important clinical decisions (e.g., when to recommend pulmonary valve replacement), cardiac magnetic resonance imaging (CMR) remains the diagnostic modality of choice.
- Repairing or replacing a dysfunctional pulmonary valve should be considered when RV end-diastolic volume (RVEDV) >160 mL/m2 and/or RV end-systolic volume (RVESV) >80 mL/m2 on CMR.
- RV normalization could be achieved with pulmonary valve replacement when preoperative RVEDV is ≤160 mL/m2 or RVESV is ≤80 mL/m2 on CMR.
- What is the Melody valve and what is it used for?
- The Melody valve consists of bovine jugular vein sewn within a platinum-iridium stent.
- Transcatheter pulmonary valve placement with the Melody valve is effective in the short term for relief of right ventricular outflow tract (RVOT) obstruction and pulmonary regurgitation in patients with surgically implanted right ventricle–to–pulmonary artery conduits.
- Melody stent fracture (MSF) with valve dysfunction is the most common indication for reintervention after Melody valve placement.
- MSF is more likely in patients with severely obstructed RVOT conduits and when the Melody valve is directly behind the anterior chest wall and/or clearly compressed.
- Pre-stenting of the conduit before valve implantation improves the durability of the implanted valve.
- Congenital heart disease (CHD) and infective endocarditis (IE)?
- The risk of infective endocarditis (IE) remains a major concern in patients with congenital heart disease (CHD), whether unrepaired, palliated, or corrected. The overall incidence of endocarditis in adults with CHD is 11 per 100 000 person-years (vs. 1.5 to 6.0 per 100 000 patient-years in the general population).
- The increased survival of children with CHD and the use of conduits and prostheses in corrective surgery may have contributed to an increasing incidence of IE.
- What is Gemella haemolysans bacteria?
- Gemella haemolysans is a Gram-positive coccoid, catalase-negative, facultative anaerobic microorganism of the mucus membranes in humans.
- It is able to cause severe and generalized infection as opportunistic pathogens, and it has become an emerging bacterial etiology in IE.
- Generally, Gemella endocarditis is associated with previous valvular damage or a poor dental state.
Delaney, Jeffrey W., et al. “Covered CP stent for treatment of right ventricular conduit injury during melody transcatheter pulmonary valve replacement: results from the PARCS study.” Circulation: Cardiovascular Interventions 11.10 (2018): e006598.
McElhinney, Doff B., et al. “Stent fracture, valve dysfunction, and right ventricular outflow tract reintervention after transcatheter pulmonary valve implantation: patient-related and procedural risk factors in the US Melody Valve Trial.” Circulation: Cardiovascular Interventions 4.6 (2011): 602-614.
Bokma, Jouke P., et al. “Preoperative thresholds for mid-to-late haemodynamic and clinical outcomes after pulmonary valve replacement in tetralogy of Fallot.” European heart journal 37.10 (2016): 829-835.
Aslam S, Khairy P, Shohoudi A, Mercier LA, Dore A, Marcotte F, Miró J, Avila-Alonso P, Ibrahim R, Asgar A, Poirier N, Mongeon FP. Shone Complex: An Under-recognized Congenital Heart Disease With Substantial Morbidity in Adulthood. Can J Cardiol. 2017 Feb;33(2):253-259. doi: 10.1016/j.cjca.2016.09.005. Epub 2016 Sep 29. PMID: 27956040.